Circuit interrupter



0. VON MEHREN CIRCUIT INTERRUPTER Jan. 23, 1951 5 Sheets-Sheet 2 Filed May 2, 1947 aw nw WITNESSES: 52

INVENTOR 0awa/aran/iie/rren,

ATTORNE Jan. 23, 1951 o. VON MEHREN CIRCUIT INTERRUPTER Filed May 2, 194"! 5 Sheets-Sheet 5 INVENTOR Oswo/dvan Jkhren. @lz ja/ ATTORNE WITNESSES:

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Jan. 23, 1951 o. VON MEHREN CIRCUIT INTERRUPTER 5 Sheets-Sheet 4 Filed May 2, 1947 INVENTOR 0514 0/01 0/7 Mebren.

WITNESSES: d

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ATTORNEY Jan. 23, 1951 o. VON MEHREN CIRCUIT INTERRUPTER 5 Sheets-Sheet 5 Filed lay 2, 1947 a s a Movable Ra. c/r

N V E N T O R OJm/aroa/Webran.

WITNESSES:

( ATTORNEY Patented Jan. 23, 1951 UNITED STATES PATENT orFlacE CIRCUIT mrnanpe'rr n" Oswald von Mehren, Lrain,'-..Qhio, .assignorztos. Westinghouse Electric.'Corp orati0n; ,East Pitts; burgh, .Pa.,. a corporation of "Pennsylvania ApplicationMayfit1947, Serial N 0. 745,469 I iziciaims; 1

This invention.relates to circuit, interrupter-s ingeneraL. and, .more particularly, .to operating;

mechanisms for the contact structuresthereof. Thegeneral objecttofmy;inventio riato provide improved operatingnmchanism for a circuit;

interrupter in whicha large kinematic ratio between operating rodand moving contact ispossible. during. theinitial portion of the closing.

stroke, andrimwhich a large static-.contactpressure maybeobtainfidwhen the interrupter is.

closed;

Anothenmoreepecific object is. to provide an: mprovedqo eratin h n sm for a r i -in terrupterinvolving two relatively movableracks, one of-tthezraeks being relatively stationary and thepother being formed. on, theside of the move. ablecontact, and to interconnect the tworela.

tively movable racks by the use of gearmeans whichg is; actuatedby an eccentrically. pivoted operating; o

Anotherobjectis-to provide an improved cir cuit interrupter of the type utilizing. a. terminal bushing extending interiorly into casing means andhav-ing an improved operating mechanism;

secured to the interior end of the terminal 'bush-,--

ing which will be of ahigh-speed .simplifiedetype.

Preferably l employ a rack formedon the sideof I the. movable" contact and meshing. with. gear means which cooperatewith a,stationary rack.

secured to theinterior end of the terminaljb'ush-.

ing.

Further objects and advantages will readily,

becomeapparent upon a'reading of'the follow.- ing, specification, taken in conjunction with the drawings, in which:

Figure l isa side elevational view of a circuit,

interrupter embodying my invention;

Fig. 2 is avertical sectional view through the interrupter shown in Fig. 1,. the contacts being shown in the closed circuit position;

Fig. 3 is an enlarged view, partly in'section, .ofj

myimproved operating mechanism, taken along the line.III.-11I of Fig. 4, looking in the direction of the arrows, and the contacts being in the fully open circuit position;

Fig. 4-. is asectional view, taken along the line IVIV of. Fig. 3;

Fig.v 5 is a sectional view ofmy 'improvedop crating mechanism, taken alongthe:1ine"V-'-V of F Fig. dis a diagrammatic. View. uni natm m principles involved in,the operation .oi'my improved mechanism;.

Fig.. is a raphfi lustrat na he princ ples' my, inv n n; and T 8' shows a travelcurve"ofthepositiono? the eccentric pivot during: successive closing positions.-

Reierring toth'edrawings; and more particu--- larly 'to- Figural thereof, the reference numeral I designatesa base upon which is positioned Ver ticall'y-extending framework including a pluralityof upright ang-le irons 2 braced by diagonallyextending angleirons 3-and forming a support:

platform l at the upper'end'thereof. The plat form 4 rigidly- -supports =in place a circuit inter-- rupter generallydesignated by thereference numeral 5; ancl including a high-voltage-condenser bushing E extendingthrough the: support? L and having the: lower: end thereof interiorly positioned within casingmeans generally des-.

positioned withinthe porcelain 8'is .an'insulating cylinder 9' containing a suitable arc-extinguishfiuid Iii, in this instance circuit"breaker oi1,'fi1ling the. casing llto the level indicated.

Immersedfwithin the liquid Ill isan arc-=ex tinguishingstructure generally designated-by the reference numeral; which-may be of various types, but is preferably of the typemore-clearly, set forth in United States patent applicationfiled May 2, 1947, Serial No, 745541, by Robert Friedrich and Oswald von Mehren, and assigned the assignee of the instant application. The contact structure within the extinguishing structure; I i is operated by an operating mechanism gene.

erally designated b'ythe. reference: numeral. l2; and shown more clearly in .Figs. 3 5: inclusive,

An insulating operating. rod 2 i 3 :is: employed. to.

actuate the-mechanism i 2 the operating-rod l 3sis. .pivotally connected; at: l ,4; to a crank arm:.l5;pivotally mountedion a shaft The upperend; of

I which :may be operated externally, of the. in-

terrupter 5ri-=by any-.ssuitable means (notshown);

Certains. structural features of the interrupter; shown are set forthzandiclaimedin United States:

patent application filed tA-pril .30', 1945, ,Serial No. 591, 04J7, nowPatentiNumb'ers2534;920; Dec. 19',

1950, by Leon R. Ludwig. and Benjamin}. Baker,

and assigned to the assigneeoi'tlie instanta'pplication.

Before going into; the; specific:str-ucturai. de

tails of my improved 1. operating mechanism, it may be desirable to make a study of the principles thereof; as setforth more fully :in Ei'gs- 6 and 7 i of the drawings. In circuit breaker design, the problem often arises of providing an operating mechanism combining the following requirements:

(1) Straight-line motion of the moving contact.

(2) Large kinematic ratio between operating rod and moving contact.

(3) Large static contact pressure when breaker is closed.

The last two requirements work against each other and can not be satisfied by the use of fixed fulcrums. So far, complicated and roomy link arrangements have been used for this purpose. The invention forming the subject of the present disclosure aims at providing a simple, effective, and compact device which is susceptible of extensive variations for its adaption to the dimensional requirements of each application.

Referring to Fig. 6, which diagrammatically illustrates the principles of my invention, the device consists of a fixed rack A, a moving rack B, a gear (or set of gears) C connecting the two racks, and an operating rod D. Considering the simplest arrangement, where only one gear is used to connect the two racks, we see that if the operating rod D were to engage the connecting gear C at its center (not shown), the arrangement would simply be an application of a wellknown elementary mechanism, where the ratio of motion and of force between the operating rod D and the moving rack B would be constant (in this case, 1/2 and 2/1 respectively).

If, however, the operating rod D is made to engage the connecting gear C through an eccentric pivot E, the lever ratio between the operating rod D and the moving rack B would no longer be constant, and its instananeous value would be found in the expression:

R +1" cos L 2R (1) SD=R0+T sin 6 (2) while the corresponding travel of the moving rack is expressed by For the sake of illustration, let us give a numerical value to the radii R and r by making R'=3 and 1:2. By substituting these values in the above formulas (1), (2) and (3), the three functions have been plotted in Figure 7 in the corresponding curves la, 2a and 3a in terms of various values of the angle 0 through one complete revolution of the connecting gear.

By observing and comparing these curves, we see that as long as we limit the total angular displacement of the connecting gear to less than one turn, we have a large selection of combinations to suit any application.

For instance, if we were to choose a rotation of 180 from 1r to 211-, we would have this result:

Travel of operating rod, curve Lever ratio at end of travel, curve |a=.833

This would give us the normal average kinematic ratio of 1/2 as if the gear had been engaged at its center, but the final lever ratio would be .833 instead of .5.

On the other hand, were we to choose this same half turn rotation from 1r/2 to 31r/2, we would have:

Travel of operating rod, curve Travel of moving rack, curve Lever ratio at end of travel, curve la=.5.

This would give us a kinematic ratio of .287 instead of 1/2 while the final lever ratio would be the same as if the gear had been engaged at its center. Of course, there is an infinite choice for all the initial and final angular positions of the pivot E, and also the results can be altered by adopting a different value for the ratio r/R.

To incorporate the above-mentioned principles into a, mechanism for causing straight-line motion of the movable contact in a circuit interrupter, reference may be had to Fig. 3, which shows my improved mechanism i2 in the open circuit position. Referring to this figure, and also the sectional view set forth in Fig. 4, it will be observed that I have provided support means I! threadedly secured to the lower end of the hollow terminal stud l8 extending interiorly through the bushing 6. The support means l1 may be clamped in position by a bolt I!) (Fig. 5) which passes through an aperture 20 of the support means ll (Fig. 3). The support means I! includes a downwardly extending guide housing 2i, the configuration of which is more clearly shown in Fig. 4. Guide rollers 22 are employed to assist in guiding the vertical motion of the movable contact 23, which telescopes within the hollow terminal stud it as shown. Above the line 24, the movable Contact 23 is rectangular. Below the line 24, the movable contact 23 has a, rod-shaped configuration, the purpose for which will appear more clearly hereinafter.

Secured to two side plates 25, 26, integrally formed with the support means H, are a pair of stationary racks 21. Meshing with the racks 21 are a pair of outside gears 28 of a gear carriage generally designated by the reference numeral 29. A supporting framework, generally designated by the reference numeral 30, interconnects the two concentrically mounted outside gears 28. The framework 3% comprises bridge portions 3|, more clearly shown in Fig. 3, which connect each outside gear 23 with a large central or third gear 32. The third gear 32 meshes with a rack 33 formed on the side of the movable contact 23.

The lower end of the insulating operating rod I3 is forked and each leg 34 of the forked portion makes an eccentrically pivoted connection with the supporting framework 30. The ofi-center pivot connection 38 for the operating rod I3 is more clearly shown in Fig. 3. Jutting outwardly from each outside gear 28 is a shaft portion 35 about which is mounted a sleeve 36 which is guidably slid in a guide slot 31 formed in each of the two side plates 25, 26.

From an inspection of Figs. 3 and 4, it will be observed that the off-center pivot 38 will make a travel curve, as more clearly shown by the curve 33 of Fig. 8, during successive closing positions ofrthevinterruptervs Im-zotherrwordsruponadowmward closing: movement aof-i'theroperating red: l 3;, the:eccentric:pivot43iimviil:firstunove;moresclosely, tor-the stationaryygearirackstfli andithen asithe closing-movement.continues; it will :move toward;

31;, greater moment armuto: bearrupon zthe: moving:

the-left as :shown"in-"Fig; to therebyrbringcontact- 23 110: increase the contact'gpressuregwhem the break'en'is' irrthe closed circuit-positions It will be notedethat thes'gearimeanmincluding: the three-gears 28} 32;: donnotfimak'e aicompletee revolution, a complete revoluti'om notibeingzpossi sible-because of tl're two bridging portions-:3-l

Referring to 2; it will be observed that thev.

line 24; being the pointlof 'separation between the rectangular: and' rod' shaped, portions f i'the 1: movable contact 2 3 will make engagement -withr. aninsulating bridge- 4fi which-hasIsecured thereto two-insulating rods 41 the lower 'ends of which' malre rpivotal connection, at 42; to avi-pair oflevers 43f th'elatter-being 'pivotally' mounted on- The inner: ends of the levers \fla make pivotal connection, at 45, to astationary pivots 445 simultaneously withdownward movement of the rod-shaped portion of "contact 23 so-that the "two-'- contacts 23, 46make simultaneousengag-ement with the relatively-- stationary intermediate -con= tact- 4'1.

Mehren application.

The: electrical circuit-- through?- theftwobreak interrupter includes line' terminal," 50-, hollow terminal stud- I 8; supportmeans "I 'lfflexible conductorfil slider-contact'-52; movable contact 23, intermediate contact 41, lowermovablecontact 46; lower support-plate 53 to lowez' lineterminalffl.

From-the foregoing description; it"wilrbe apparent that I have provided i an improved oper"-' ating' mechanism :for i a movable contact"'which" combines a high-speedmotionat the initialpor-' tion of the closing stroke withislower motion near the end of .the stroke with a; greater static contact pressurebeing brought into play, at'th'e extreme end of the closing'stroke; Thus, during the. major portion of the: closing stroke, where merely speed is required'and'contactl-pressure is not" needed, the mechanism is\..hig h'-speed' in;

operation. Near the. endiofthe'closingstroke, where it'isi important to obtain a high degree of static contact pressure, my improved'mechae nism is-operable to provide agreater lever arm acting upon the movable contact23Zbytheposi-- tion .of the off-center pivot 38 "atthe end ,ofjthe.

closing stroke;

The rollers 22 guide the downward ,movement.

of "the ,movable contactv23' andprvent its lateral movement, thus insuring, firm :immeshment with.

the center gear 32.

During, the o ening operation the operating,

rod .11 Ii,v ismovedjupwardly. by clockwiseirotation of ,the shaft l6 -to thereby, cause .upwardmovee ment of; the gear. carriage, 29.v The upward; movementiofithe gear carriage .29. causesupward-i travel of, ther movable contact 23, the compress,

This construction" is set forth": and claimed in theaforesaid Friedrich and" von' 6 siomsprings -48;v thereupon:isimuitane'ouslyycau'ser ingc u-pward movement ofrthe =rods;.-4:l .and downs ward 2 separating motion ;of: the 2001113810122 46rfrom the intermediate; relatively stationary: contact v 5? 41;. Thus; the; mechanism is..operablertoccreate" twoaisimu'ltaneous breaks during the opening; Op? eration.:. As isv well-known; to". those skilledLin; theiartgfluid under.-pressure is employed to effect rapid extinction i of. thezarcs drawn. at the two,- 'breaksa Althouglrl haveshown and :described a specific: structure; it is:ito;.b'erclear1y@ understood that :the. same was 'merelyifor the purpose "of "illustrationandi that changes and modifications mayz-readi'lyi 5 be:- made: therein by. those: skilled in: the art; without departing from the spirit :and scope of I the appended claims.

I; claim as my: invention:

1.: In a: circuit interrupter, means;.-defining; a1,

i rfixed rack; aim'ovable contact having a:: rack: formed along one side thereoi-..- rotatable: gear; means rotatable. about amoving axis meshing with both the fixed rackwand the rack-formedi on th'eside of the movable contact te cause by;

25;:- suchrotation opening and closing movements of the movable contact, a movable operating rod-'- connected to the rotatable gear means on: eccentric pivot 'with respect to the axis of rotation=of=the gear means-to 'causethe actuation f=thereof andhence opening and closingv move ments of themovable contact.

2. In a-circuit interrupter, means defining a pair of stationaryracks, a pair of rotatable ea-rsrotatable-about a'moving axis andmeshz-ing with the pair of racks, movable support means interconnecting the two rotatable gearsand including a third movable gear, a movable contact having a rack formed along oneside thereof, the third movable gear meshing with 401therack formed on the movable contact, and

movable operating rod means pivotally connected-'to--the support means on an eccentric pivot with respect to the axis of rotation of the pair of rotatable gears for causing opening and 45, closing movements of the movablecontact;

3. In a circuit interrupter, a pair of relativelymovable contacts, one of the contacts being movable-andhaving arack formed along one-side thereof, a' movablegear carriage including three 50,c0ncentrically positioned movable gears rotatableabout a1moving axis, a pair of stationary racks, meshing With the two outside movable gears; the middle gear meshing with the rack formed on-the side'of the movable contact, and

an operating" rod eccentrically pivoted to the "movable gear carriage'to cause'the actuation thereof, and hence opening and closing movem'ents-of the movable contact.

4. Ina-circuit interrupter, a pair of relatively:

movable racks, a pair ofrelative1y'movab1e contacts cooperable to establish-van arc, oneofthe racks being forme'd'on one or" the contacts, movable gear means rotatable about a moving; axis and'meshingwith the two racks to causeprela- 5vtive-movement therebetween, and an operating rod eccentrically pivoted with respect to, the

moving axis connected to the movable gear meansto cause the actuation thereofand hence opening and closing movements of thecontacts, 5; In, acircuit interrupter, casingkmeans, an. insulating terminal bushing supportedadjacent, one end of the casing means and having. one end ,thereofextending interiorly within the casing ,means, an operating ,mechanism secured; to. 75,the interiorly. extending. end I of, the. terminal:

bushing and including a relatively stationary rack, a movable rod-shaped contact telescopically related to the terminal bushing and having a. rack formed along one side thereof, movable gear means forming a part of the operating mechanism and meshing with both the relatively stationary rack and the rack formed on the side of the movable contact, an are extingushing structure positioned adjacent the other end of the casing means, contact means including the movable contact for establishing an are within the arc extinguishing structure, an operating rod, and the operating rod being connected to the gear means on an eccentric pivot to cause the actuation thereof and hence opening and closing movements of the movable contact.

6. In a circuit interrupter, casing means, an insulating terminal bushing supported adjacent one end of the casin means and having one end thereof extending interiorly Within the casing means, an operating mechanism secured to the interiorly extending end of the terminal bushing and including a relatively stationary rack, a movable rod-shaped contact telescopically related to the terminal bushing and having a rack formed along one side thereof, movable gear means forming a part of the operating mechanism and meshing with both the relatively stationary rack and the rack formed on the side of the movable contact, an arc extinguishing structure positioned adjacent the other end of the casing means, contact means including the movable contact for establishing an are within the arc extinguishing structure, an operating rod, rotatable means for actuating the operating rod disposed adjacent the end of the casing means which supports the terminal bushing, the operating rod extending substantially along the side of the interiorly extending end of the terminal bushing to the operating mechanism, and the operating rod being connected to the gear means on an eccentric pivot to cause the actuation thereof and hence opening and closing movements of the movable con- 7 tact.

'7. In a circuit interrupter, a substantially elongated cylindrical casing having a weatherproof exterior, an arc extinguishing structure supported interiorly of the casing adjacent one end thereof, terminal means for the interrupter disposed adjacent the said one end of the easing, a high voltage terminal bushing having the lower end thereof projecting interiorly within the casing and supported adjacent the other end of the casing, an operatin mechanism secured to the lower projecting end of the terminal bushing, contact means associated with the arc extingushing structure including a movable rodshaped contact for establishing an arc therein, the movable contact being adapted to be telescopically received by the terminal bushing in the fully open circuit position of the interrupter, a rack formed along the side of the movable contact, a relatively stationary rack forming a part of the operating mechanism, movable gear means meshing with both the relatively stationary rack and the rack formed on the side of the movable contact, an operating rod, and the operating rod being connected to the ear means on an eccentric pivot to cause the actua tion thereof and hence opening and closing movements of the movable contact.

8. In a circuit interrupter, a substantially elongated cylindrical casing having a weatherproof exterior, an arc extinguishing structure supported interiorly of the casing adjacent one end thereof, terminal means for the interrupter disposed adjacent the said one end of the casing, a high voltage terminal bushing having the lower end thereof projecting interiorly within the casing and supported adjacent the other end of the casing, an operating mechanism secured to the lower projecting end of the terminal bushing, a relatively stationary contact and a movable rodshaped contact cooperable to establish an are within the arc extinguishing structure, the movable rod-shaped contact being adapted to be telescopically received by the terminal bushing in the fully open circuit position of the interrupter, a rack formed along the side of the movable contact, a relatively stationary rack forming a part of the operating mechanism, movable gear means meshing with both the relatively stationary rack and the rack formed on the side of the movable contact, an operating rod, the operating rod being connected to the gear means on an eccentric pivot to cause the actuation thereof, and hence opening and closing movements of the movable contact, rotatable means for actuating the operating rod disposed adjacent the said other end of the casing, and the operating rod extending interiorly of the casing substantially along the side of the projecting end of the terminal bushing.

9. In a circuit interrupter, an insulating casing, an arc extinguishing structure disposed interiorly of the casing and supported adjacent one end thereof, terminal means for the interrupter positioned adjacent the said one end of the casing, a pair of movable contacts movable adjacent opposite ends of the arc extinguishing structure, operating rod means interconnecting the motion of the pair of movable contacts, a terminal bushing projecting into the casing adjacent the other end thereof, an operating mechanism secured to the lower projecting end of the terminal bushing, one of the pair of movable contacts being adapted to be telescopically received by the terminal bushing and having a rack formed along one side thereof, the operating mechanism including a relatively stationary rack, gear means meshing with both the relatively stationary rack and the rack formed on the side of the movable contact, an operating rod, and the operating rod being connected to the gear means on an eccentric pivot to cause the-actuation thereof.

10. In a circuit interrupter, an insulating casing, a high voltage terminal bushing supported adjacent one end of the casing and having the lower end thereof extending interiorly within the casing, an arc extinguishing structure disposed interiorly of the casing and supported adjacent the other end of the casing, terminal means for the interrupter disposed adjacent the said other end of the casing, the casing having an exterior of weatherproof material, a pair of movable contacts associated with the are extinguishing structure and movable adjacent opposite ends thereof, an operating rod interconnecting the motion of the pair of movable contacts, means biasing the pair of movable contacts to the open position, an operating mechanism secured to the lower projecting end of the terminal bushing, one of the pair of movable contacts being adapted to be telescopically received by the terminal bushing and having a movable rack formed along one side thereof, the operating mechanism including a relatively stationary rack, movable gear means meshin with both the relatively stationary rack and the rack formed on the side of the movable contact, an operating rod, and the operating rod being connected to the movable gear means on an eccentric pivot to cause the actuation thereof and hence opening and closing movements of the movable contact.

' 11. A circuit interrupter including casing means, an insulating terminal bushing supported adjacent one end of the casing means and having one end thereof extending interiorly within the casing means, an operating mechanism secured to the interiorly extending end of the terminal bushing and including a relatively stationary rack, a movable rod-shaped contact telescopically related to the terminal bushing and having a rack formed along one side thereof, movable gear means forming a part of the operating mechanism and meshing with both the relatively stationary rack and the rack formed on the side of the movable contact, an arc extinguishing structure positioned adjacent the other end of the casing means, contact means including the movable contact for establishing an are within the arc extinguishing structure, an operating rod, and the operating rod being pivotally connected to the movable gear means to cause the actuation thereof and hence opening and closing movements of the movable contact.

12. A circuit interrupter ported adjacent one end of the casing means and having one end thereof extending interiorly within the casing means, an operating mechanism secured to the interiorly extending end of the terminal bushing and including a relatively stationary rack, a movable rod-shaped contact telescopically related to the terminal bushing and having a rack formed along one side thereof,

including casing means, an insulating terminal bushing sup- 10 movable gear means forming a part of the operating mechanism and meshing with both the relatively stationary rack and the rack formed on the side of the movable contact, an are extinguishing structure positioned adjacent the other end of the casin means, contact means including the movable contact for establishing an are within the arc extinguishnig structure, an operating rod, rotatable means for actuating the operating rod disposed adjacent the end of the casing means which supports the terminal bushing, the operating rod extending substantially along the side of the interiorly extending end of the terminal bushing to the operating mechanism, and the operating rod being pivotally connected to the movable gear means to cause the actuation thereof and hence opening and closing movements of the movable contact,

OSWALD VON MEHREN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 595,732 Pitt Dec. 21, 1897 860,433 Andersen July 16, 1907 1,381,344 Samuels et a1. June 14, 1921 1,512,647 Stevens Oct. 21, 1924 2,163,559 MacNeill June 20, 1939 2,422,569 Leeds June 17, 1947 2,450,268 Bazley Sept. 28, 1948 FOREIGN PATENTS Number Country Date 462,425 Germany July 10, 1928 769,242 France June 5, 1934 

